Several publications and patent documents are cited throughout the specification in order to describe the state of the art to which this invention pertains. Each of these citations is incorporated by reference herein as though set forth in full.
Environmental heavy metal contamination, which is implicated in many diseases and agricultural losses (1-2), poses a challenge with a price tag for remediation estimated at upward of $200 billion in the US alone (2). Heavy metals, such as cadmium (Cd2+), undergo aberrant capping reactions with the thiol groups of proteins and some coenzymes, displace endogenous metal cofactors from their cellular binding sites, and promote the formation of reactive oxygen species (2). Engineering plants and microbes for the detoxification of heavy metal contaminated soils and waters traditionally relies on the modification of existing metabolic pathways and/or metal transport and sequestration systems (3-7). Although transgenic methods can enhance heavy metal tolerance and accumulation, the inherent biochemical properties of the proteins introduced often limit the extent of the enhancement. Engineering the proteins that are used for this purpose can offset inherent limitations on tolerance to and/or accumulation of heavy metals so as to broaden the range of molecular tools available for environmental clean-up (8). An objective of the present invention is to provide such plants and methods of use thereof for environmental bioremediation.